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From a physics standpoint, getting men and material to and from the Lagrangian points would be vastly cheaper than getting them to and from the moon. Until we could utilize the raw materials of the moon to produce things, it isn't going to be cost-effective to have a moon presence.

The moon was original part of Earth that was torn off. It recollapsed into a sphere (as did Earth) because of it's own gravity. The reason it DOESN'T change it's visible side is because of tidal locking. It's not a perfect sphere so one side was pulled on more than the other, which eventually causes the rotational and revolutional periods to become equal (Pluto and Charon are so simliar in size that both have become tidaly locked with each other, and always show the same "face" to each other). Our Moon has become locked with Earth, but Earth, because of it's larger mass, has not become locked with the moon, but is in the process of doing so. This is what is causing the moon to drift farther out (though the orbit is completely stable. if Earth finally became tidally locked than the moon would simply stop drifting out. the Sun will die before this happens though). Earth's rotational speed is also slowing down because of this tidal locking. It's estimated that the planet had an original rotational speed of about 15 hours. If it became completely tidally locked, the rotational period (and the length of a day/night cycle) would be 28 current days.

In a perfect two body system. The lagranian point is stable. In our solar system, not even a normal orbbit is stable. So any station at L1 would need to correct it's possition once in a while. But this is already true for ISS. No problem.

the reason to put it at 5/6 of the way to the moon (or so) is that that is the location of a LaGrange point, a point in outer space where the gravity between the earth and the moon cancel each other out perfectly, so a space station at a LaGrange point (in this case L1) wouldn't have to use thrusters to maintain a stable orbit and would never leave it's stable orbit around the earth. if you put it on the moon, you'd have to overcome lunar gravity to leave, costing both fuel and money.

a space station at a LaGrange point (in this case L1) wouldn't have to use thrusters to maintain a stable orbit and would never leave it's stable orbit around the earth

That's not true. L1, L2, and L3 are all gravitationally unstable points. A space station at L1, if nudged out of position even slightly, will tend to spiral inward toward Earth or outward toward the moon. The L4 and L5 points are the only stable Lagrangian points in a two-body system.

That's not true. L1, L2, and L3 are all gravitationally unstable points. A space station at L1, if nudged out of position even slightly, will tend to spiral inward toward Earth or outward toward the moon. The L4 and L5 points are the only stable Lagrangian points in a two-body system.

Even then the actual L4 and L5 points are not entirely stable in the real solar system, because the solar system has a lot more that two bodies and nothing is a point mass. This also means thet the "points" are actually regions. Which is why Jupiter can capture many asteroids in it's L4 and L5 points with Sol.

I have mod points, but since I work on SOHO and someone modded the parent "Informative", I have to straighten things out:)

GiliadGreene has made some [slashdot.org] good [slashdot.org] points [slashdot.org]already about SOHO being in a halo orbit around the L1, not at the actual L1 "point".

Orbit corrections are performed every 17 weeks (four months, not one).

The halo orbit is much saner than trying to stay at the L1 point, and it attenuates solar interference. Ironically, the COMSAT link that DSN uses to get data from Madrid to California gets more solar interference than the spacecraft to ground link.

If the SOHO satellite and the proposed space station are both at L1, how close will they be? Visible distance?

SOHO is at Earth/Sol L1, this station would go at Luna/Earth L1. Different points. The size of the "points" is a function of the mass and mass distribution of the larger 2 objects. In the case of the proposed location these objects are Earth and Luna.

uh, I don't mean to point out the obvious, but you don't need thrusters to stay in a stable 'orbit' on the surface of the moon. If they built a station on the moon, I really doubt it'd go very far on it's own.

Of course, it'd be easier to leave from L1, as they would have to fight the gravity of the moon to get back into space. I hope that's what you meant...

You know, a couple of rounds of budget cuts later, their next grand space station will be another useless pile of expensive junk just like the first one. The problem is that it will be squatting one of only five stable points at which long-term space projects can be built.

Well, I don't like it. What gives NASA the right to squat on what is probably one of the five most valuable places in the universe (from our perspective)? Will there be a deal arranged that in 50 years, when a better space agency comes up with a better project for the liberation point, they'll move their junk out of there? There had better be. Seriously, the UN has to get on this fast. Right now, the USA has basically called dibs on two of the five liberation lunar liberation points, plus there's that second-generation telescope that they want to put into the liberation point behind the earth, where it is always shielded from the sun. Well, this is the ideal place to build a telescope, and once something is there, everybody else, even people with a better telescope idea, are shit out of luck. They'll have to spend billions to make heat shielding because NASA is squatting on the one spot where the heat shielding is natural (permanently in the shadow of Earth).

If I were the UN, I would set a squatting limit of 30 years on any given liberation point. If somebody wants to use it after that, whoever was there before has to get the fuck out and clean up after themselves. I think it's likely that in 30 years all the liberation points will have something, and in another 30, countries will be duking it out over who gets to go there next. The people who want it most will have to compensate the other people who want it. In any case, this is not too soon to be thinking about making international laws about this.

Apples and oranges. Having a station in zero gravity is really useful for launching probes and ships from, and as a gateway between the Earth and the rest of the solar system. Having a moonbase gives you mining capabilities and so forth.

They're both very important aspects of stepping into space, for different reasons.

Because the whole point of staging at L1 is that it allows low-energy transfers to other points in the solar system. Launching a trip to Mars, for example, from L1 would require much less energy than from either the surface of the Earth, or low Earth orbit, or the surface of the moon.

Of course, this ignores the biggest problem with the L1 point: it's unstable. A body placed at L1 will tend to either fall inward toward the Earth or outward toward the moon at the slightest push. Any space station at L1 will have to correct its position regularly, probably using simple chemical rockets. These rockets will have to be refueled periodically and so on, making for a nontrivial amount of effort to keep an L1 space station in position.

The L4 and L5 points, on the other hand, are gravitationally stable. If a body at L4 or L5 starts to drift out of position-- due to a collision or outgassing or whatever-- the Earth-moon system will tend to pull it back to the point of stability again. But since L4 and L5 are farther from Earth than L1 is, it takes more time and energy to get there from LEO.

They aren't global attractors. Meaning that if I stick something on the other side of the solar system, it's going to be pulled towards Earth, not the two stable Lagrange points.

However, they are locally stable. Meaning that anything put in that general area gets pulled into the Lagrange point. The 'general area' is mathematically defined by the gravitational equations, but you can think of it like a dip in the side of a bowl. A marble placed in the bowl rolls toward the bottom. But if you put the marble close enough to the dip, it will settle there instead.

>>That's all well and good, but you have to get TO L1 FROM the Earth or low Earth Orbit, or the Moon before you can enjoy the benefits of a low energy launch.

Wouldn't getting your launch ship there in the first place, nullify any benefits of relaunching from there?

Well, if you are putting a ship together in space, like the ISS, then it is worthwhile. You send up pieces that get assembled in the low gravity and then *launch* from the low gravity point. You save energy by not having to break out of LEO with such a large vehicle. Otherwise, the vehicle will have to provide it's own propulsion for the breaking away - a costly proposition.

Think of getting to L1 as storing kinetic energy in the components of the vehicle. After construction, launch can entail causing the craft to drift toward the sun to use the slingshot effect for accelleration. After the craft is accellerated, onboard propulsion can be used to provide the extra impetus to extend the curve of the orbit to the point where the craft will end up at a predetermined solar destination.

The only advantage I can begin to imagine would be a large reusable shuttle that you didn't have to launch from Earth every trip, but you still have to launch cargo, crew, fuel and supplies for each trip, and you have to have a pretty big ship or several small ships to get this hypothetical space-based shuttle furnished for another trip.

If you have a station at L1 you can launch the pieces of the spacecraft up from earth in parts and assemble it there, and it only has to be able to withstand whatever gravity or thrust you expect it to experience during it's mission.

On the other hand, if you build it on earth, it has to be able to survive the many G launch from the surface of the earth up into space, which would require it to be built much heavier and therefore be less efficient once it leaves earth's gravitational field.

Why carry all that extra weight around when you can construct it in orbit instead and dodge the whole issue?

I know that the X-ray telescopes they have floating out there are of the grazing incidence variety, meaning the mirrors reflect X-rays/gamma rays at small angles, in stages, so that they lose some of their energy and don't burrow into the sensors. Kind of like skipping a bullet over a lake. At too high an angle of incidence you break the surface, but if your angle is small enough it will skip indefinitely. My take on the subject is that we don't have any materials heavy/stable enough to reflect high energy radiation.

My take on the subject is that we don't have any materials heavy/stable enough to reflect high energy radiation.

The problem is that conventional materials of all types misbehave as photon energy substantially exceeds the chemical binding energies. You go from having materials acting like ideal classical conductors or dielectrics interacting with photons that act more or less like classical EM waves [normal reflection and transmission], to having materials that act like a set of quantum energy levels and photons that act like particles [photoelectric effect], to having materials that act like a diffuse sea of particles that scatter photons which also behave like particles [Compton scattering].

As the valence shell binding energies in atoms are at most on the order of a few tens of eV, there is a hard upper limit on the frequency of radiation that conventional optical elements made of normal matter can handle.

The limit's mushy in one respect, in that grazing-incidence devices see an effective frequency that's inversely proportional to the angle of incidence. However, practical devices limit the benefit of this to between a factor of 10 and a factor of 100 (so you can see some x-rays, but gamma rays are still tricky).

Non-conventional optics made of normal matter can still work under some conditions. Because the inter-atomic spacings in crystals are in the same ballpark as high-energy photon wavelengths, you can get diffraction occurring when an x- or gamma-ray beam passes through a crystal (due to scattering off of inner-shell electrons and the nuclei). This is commonly used to identify materials (x-ray diffraction patterns have been used to image atoms in everything up to and including crystals of viruses). Gamma ray telescopes using crystalline blocks to construct diffractive optics have been built.

Lastly, the final and most difficult way to cheat involves using plasma as a mirror. As it's a gas of free ions, it should have near-perfect reflection even at high wavelengths (subject to a few probably-nontrivial conditions). Keeping a cloud of ions confined to an optically flat surface is left as an exercise for the reader.

With the insane ammounts of cost overruns and mismanagement in the ISS project, who thinks that a jaded congress is going to vote a new space station [no matter how much MORE useful than the ISS it may be] any funds whatsoever?

This may be almost a replacement for ISS. It's become fairly obvious that certain nations (*ahem Russia*) are intent on using the ISS as SpaceDisney, letting any jackass with $20M up there. So NASA might be trying to get their own space station back. ISS was really a political animal anyway (Congress loved the idea of unity or some similar crap).

It's like a playground spat: "We don't want you bringing your friends to our treehouse, it's for members only!"

Of course, the reason Russia can afford to keep contributing to the ISS, is because of those "jackasses". The US needs to stop whining. Russia obviously has a huge interest in the ISS, or they wouldn't bother selling rides to finance their parts of the project.

Yes, it is true that the International Space Station has taken a horrendous amount of money that could've been spent on real science. I admit that I'd like to see more money spent on real science missions like probes to Pluto or Europa or on more Space-based telescopes, but unfortunately as these devices increase in size (satellites, space telescopes, probes, etc.) it becomes infeasible to launch them in a confined shuttle (I believe Chandra X-ray telescope reached the volume limits on what could be launched in one piece).

That said, we need to be building an infrastructure for launching larger and more complex devices into space. This requires places where things can be assembled once in orbit, places such as the ISS or another station at a Lagrangian point. In and of themselves, these stations aren't spectacular, they don't produce good science and they are very expensive, but they need to be created to assist other scientific endeavors as our technology continues to develop. As an example, routers, fiber, and transcontinental backbones are expensive and to the layman, they produce no real science or pretty pictures, but they are necessary as an infrastructure over which people can do some really cool things.

Anyway, I think that even if this doesn't get passed by congress or the things run behind schedule, it is good that we are at least PLANNING to do some really cool stuff like this.

Not really. The Space Shuttle actualy has a larger cargo capacity than the Apollo units ever got close to.

The Saturn V was designed to do two things. Escape the Earth's gravity well (or at least the great majority of it) and prove to the Soviets that if we could land a man on the moon we could damn sure land a hydrogen bomb on Moscow.

The Shuttle is a little more utilitarian. It is not deisigned to escape as much of the gravity well but rather focuses on providing a method of getting usefull stuff into orbit.

Saturn V might be a usefull way to get stuff very far away from Earth very quickly (a manned Mars mission probably won't use shuttle like craft) but it's not much for cargo capacity. The famous golf clubs had to be specialy designed and smuggled on board.

There is only room for three people for extended stays, due to Congressional budget cuts in the habitation module and escape vehicle.
The original intention is seven people.
That means the crew of three must spend 75% of their time in maintenance with only a small amount for experiments and other innovation.
Unlikely the current administration will increase funding. Many republicans hate NASA because of its environmental monitoring programs. And the previous scientific leader of NASA has been replaced by an accountant (cut and slash).

The new IMAX movie about the first three years of space station construction is fascinating.

Indeed, I think that NASA needs to spend the time being focused on smaller projects, and most importantly, they need to get the cost of a launch down. Way down. Stick with the ISS for a while. Learn how to maintain a space station for longer than a little bit (I'm looking at you Skylab). I see little to no reason why a second space station would be preferable to, say, more Chandras or Hubbles or Voyagers, or god help us all, a space shuttle without 5 hojillian individual thermal tiles.

No no, not cannabalism [sic], but half-lives. We know that the half-life of an astronaut is equal to the round trip of a mars expedition. It's something that NASA has been hiding for years, also known as the Terrible [somethingawful.com] Secret [mp3s.com] of Space [jonathonrobinson.com].

If the habitation module was built in annular form, it would be possible to have on the outermost layers offices for administration (they get the windows) and keep the scientists/engineers in the middle. Thay way administration gets to absorb the radiation first (a nice radiation burn will add to their tan).

The explorer part of me is saying, "Yay! It's about time we started building more structures in space. The Lagrange point would make a good neutral spot halfway to the moon." But then the realist in me says, "Given that NASA has proven that it can't stick to a budget, how much is this overrun going to cost?" And the article agrees with me.

Government is not the answer to promoting outer space as a new resource -- market forces have shown to be the driving force in all new ventures. We need competition in getting things into orbit, tourism to build hotels, industry to build fab plants, mining on the moon...

[sigh] I am getting really sick of hearing this bit of ideology repeated as though it were an established fact. Some things happen as a result of market forces, some as a result of government forces, and some (actually most) as a result of the combination of the two. Just because a generally capitalist economic system is healthier and more innovative than a generally socialist economic system (which is true) does not mean that "the market will take care of" everything, all the time.

If the Internet depended on "market forces," it wouldn't exist -- we'd be living in a world of multiple incompatible networks with users of any one network unable to communicate with those of others. If the highway system depended on "market forces," there would be no way in hell you could drive from one coast to the other. If education depended on "market forces," only the children of the rich would ever get an education. Etc. And if space exploration depends on "market forces," then you can kiss any chance you or your great-grandchildren have of ever getting off this planet goodbye.

the Interstate Highway System, the TVA, rural electrification, the Public Library system (just off the top of my head)... none of these were driven by these elusive "market forces" the original poster refers to.

(which is not to say that they didn't precipitate in quite a little jolt for this nation's capitalists)...

Clearly there's a bit of saliency to the argument that a little "push" by the govt. can jump-start some of these "market forces."

Some things happen as a result of market forces, some as a result of government forces

A democratic government (or any government in which the taxpayers have any influence in decision making) is a crude market. The currency is the vote instead of the dollar.

The real use of government from an industrial perspective is that it can take extreme risk; the fact that it controls land and an army means that it isn't going anywhere, so it can afford to risk losing a great deal of money without going bankrupt.

Then why not work on reducing the cost of putting stuff like lead into space? A big railgun could launch raw materials into orbit, where processing plants could actually build the heavy parts of a space station / vessel. The initial cost of a railgun would be more than a single rocket, but it would rapidly pay itself off in savings. Also, you could send stuff up in worse weather than needed for shuttle launches. A shuttle of some sort would still be needed to transport squishy / breakable things like humans and electronics.

Mostly incorrect, if you had read the article about radiation, you would understand the fundamental problem with lead is because of its weight, but not the way you are thinking. The problem is that the large nuclei (the middle of the lead atoms). These are struck by the cosmic ray, releasing more deadly radiation to the crew inside, so your precious lead sheilding would kill them all. Which is why the shielding described in the article (copied below) is a light plastic.

Radiation inside the ISS, and the now defunct Mir, is caused when the fast, heavy ions that make up cosmic rays collide with the aluminium hull, releasing a shower of secondary particles into the living quarters.

To mitigate this effect, the ISS has been fitted with additional polyethylene shielding that contains lighter atomic nuclei, which are less likely to throw out neutrons when hit by cosmic rays.

Do you know how much it would cost to lift the amount of lead you'd need into space? The earth's magnetic field deflects something on the order of 95% of cosmic rays. To acheive that in space you'd need tonnes of lead (educated guess... no figures to back this up).

Water is indeed a better shielding material, plus you can mine it on the moon (or from comets and asteroids, too) and avoid the gravity penalty of bringing up Terran water. Plus, you can use it for all sorts of other things, like growing food, storing power, and drinking. Try doing that with lead.

Not that you'd probably want to use the water afterwards, but there is no reason you can't use it beforehand.

Using waste water could work. Wether reclaimed from air, or from body fluids, this would only have been jettisoned into space or reprocessed (and reprocessed water tastes like crap!) anyway.

For that matter, waste biomatter may actually be good at shielding radiation, but you wouldn't want a leak anywhere on the inside of the station! Ewwwww!

Also, you could generate oxygen and hydrogen from water by electrolysis (well you'd have big solar panels anyway). You could use these as a propellant, since any craft at the L1 point still would need some sort of station keeping thrusters (any craft docking/departing the station, or small impacts from space debris, will change the station's balance and momentum, knocking it out of the "perfect centre" it should be sitting at), and this could provide some of the required fuel. Or you could use some of the oxygen to add to the air mix, and the hydrogen in fuel cells.

Only problem with using a liquid as a shield is that when the station is in darkness it'll be frozen, and when it's in light it'll be warm or boiling. Water changes a LOT in volume with heat, so the hull would have to be able to stand that change. And any leak where there is liquid or steam would have to be plugged, otherwise you'd end up with the liquid ejecting into space and propelling the station out of it's nice stable placement.

In the meantime, just make sure the astronauts dose up on their caffiene and they'll be fine. *grin*

I don't understand why NASA does not employ lead shielding to protect its astronauts.

Fair question, but one with a fairly simple answer.
Lets do some numbers...

To within a factor of a few, what matters in radiation shielding is "surface density", i.e. how many grams of material per square centimeter there are in your shield. So you can have a thick shield of light material, or a thin shield of dense material; for the same area they will provide the same shielding effect if they have the same mass.

Say for a moment that you want as much shielding as provided by the Earths atmosphere; that works out to be about 10 tons/square meter. (If you SCUBA dive: remember that the pressure goes up by 1 atmosphere for every 10 meters of depth. A 10x 1x1 meter column of water weighs 10 tons.)
Those ten tons/m2 can be in any form you want: a
10 km thick air shield, 10 meters of ice, 2 meters of rock, or a meter of lead.

So, you want to put a couple of guys in a spaceship and send them to Mars? Well, put them in a cramped tube, say 10 meters long and 3 meters in diameter. That gives you about 100 square meters of surface area.... or 1000 tons of shielding.

At current prices it costs about $20,000 to put a kilogram of material into low Earth orbit. The biggest rocket flown to date can put about 100 tons into orbit. With current technology you either hit up Bill Gates for the 20 billion, or you can skimp on the shielding. The space
station skimps by a factor of 300 (you get a years ' worth of background radiation in a single day).
You could also play games like have most of the spacecraft lightly shielded, but have a lead-lined "storm shelter" for the times when solar flares erupt. This works because much of the radiation comes in bursts. However, it isn't useful for going to places with continuous high levels of radiation, like Jupiter.

Eventually lead could be a solution for future space stations but it would only be practical if it came from a shallower gravity well than the earth.

Mine it on the moon and ship it up with a rail gun. For better radiation shielding find an asteroid that can be manouvered into position and hollow it out by mining it. It's former interior can be used as reaction mass to get it into position in the first place, and can be used as raw material for other construction and manufacturing projects.

Unfortunately, we cannot do anything of the sort yet. We need to make do with less adequate space stations untill the infrastructure is available to build really livable homes in space.

Of course, if you still really insist on using lead as radition shielding in the earlier stages of space exploitation then their is possibly a practical way to do it. First send up the initial inflatable habitat. Preferrably it would be sausage shaped or better yet several sausages linked into a doughnut that could be spun to gererate artificial gravity. With every subsequent mission to the station a certain amount of launch mass would be allocated to a roll of lead foil. This would be unwound over the sausges just like a gauze bandage is unwound over a wounded arm. One other thing to consider, lead has a fairly low melting point and the temperature fluctuations in space can be fairly extream. Another material or a roll of various other materials layered would probably be more effective and provide more protection from other hazards such as particles of rock and junk travelling at high velocity.

Now, to change the subject.

I do not believe that NASA as a US Gov't funded organization will ever be capable of going where humans NEED to go in space. There needs to be a new organization that receives worldwide funding from governments, industries, people in general, and even slashdotters. Such a centralized organization with more encompassing funding than NASA and other private space efforts would have a much more likely chance of getting us on the road to the effective usage of space than an underfunded government beauracracy and a few small companies competing for a paltry X Prize or quick revenue from pay TV/phone satelite launches.

Oh, just one more thing.

To quote Arthur C. Clarke(possibly not exactly) "The dinasaurs became extinct because they did not have a space program."

would it be at all possible too recreate the earths field around the space station,like give them a field generator or something. i dunno. how much power would it need to be effective at repelling the charged particles?.

I've wondered about this too. I would imagine that the power required could be generated with a combination of solar cells and a decay reactor. Both for redundancy. This would also have the advantage that you could allocate more or less power to the shield depending on whether the station was occupied, or if you needed it for other things, or if there was a solar storm, etc.

The disadvantage is that the radiation would only be redirected toward the poles, so you would still need protection there. Hopefully this would still lower costs. There is also the issue of how strong the field would have to be? Would it affect electronics in the station? Would it take away a lot of usable space with a magnetic iron pole running through the station? Is it even feasable to generate?

After the Sun and Moon.
Its been fascinating to watch it get brighter as they add more cylinders and panels every year.

The station is visible in the evenings about one week a month and mornings one week a month, so the orbit can wobble over the US, Russia, Europe, and Japan. Sky & Telescope [skyandtelescope.com] (set zip code, click on almanac)
shows pass times & locations, as do other websites.

It covers any location in the world (not just USA and Canada). It has fly-by data for hundreds of satellites (including ISS) and my personal favorites, the Iridium flares. If you've never seen a -7 magnitude Iridium flare, do yourself a favor and check it out. It's absolutely awesome.

Heavens Above will tell you where to look (direction and azimuth) and when to look - accurate down to the second!

Long range, imaginative plans... A next generation telescope at L2, shielded from the Earth's EM output by the moon... This is really exciting. Good luck NASA. I hope we get this done eventually, regardless of how much it winds up costing.

If i'm to be modded down for offtopicness, well, I deserve it, but I need to get this off my chest:

I simply can't read new scientist anymore. When the site actually loads (regardless of slashdotting), every single article they publish seems to be the scientific equivalent of the paparazzi.

I mean, really, one thing is to have a non-peer-reviewed magazine, and an entirely different thing is to intentionally publish exagerated, ridiculous, absolutely un-proved (and almost always un-provable) "facts". Even the simplest of stories is spinned beyond recognition. If a story comes up of some scientists spotting a.00001% deviation from expected results researching *.*, right after they make clear that most likely it's due to faulty measurement equipment, New Scientist will publish that they found aliens, that they have a draft of the alien invasion plan, that Einstains's GToR is therefore void, and that in fact he himself WAS an alien trying to distract us from the truth. And then they _really_ start speculating and tell you that they infer from the inforamtion that Einstein was a shape shifter and that he was also the first husband of Melinda Gates.

Now, I haven't read this article (not that I could even if I wanted to, NS' site goes DoS when they're linked from my cousin's non-porn website), but I'm sure I'll get more substance out of/.er's comments than NS (if you can believe that!)

The New Scientist is to Nature what the National Enquirer is to the New York Times. But, hey, lots of people read the National Enquirer for fun as well. Only that when people start taking it seriously that people get hurt.

In other news, radiation sheilding on the space station isn't so good.

Lead and tungsten are your friends.(I suppose that this might be a good time to come out in favor of developing a cheap, non-man-rated left vehicle, suitable for lofting dense, space-station-module-sized things into LEO...?)

The time between when Columbus "discovered" the new world and Magellen circumnavigated the globe was 30 years. It has now been 30 years since Apollo 17, the last time man visited the moon, the last time man left low earth orbit. I think it's a great failure of our race that we've dragged our feet such.

To think that technological advance is blazingly fast in this day in age is misleading. We're not doing too well at hitting the important targets. NASA might just now be waking up to this, but it's yet to be seen if their budget wakes up to it. (Nasa funding was 4% of the national budget at the height of the Apollo program, it's less than 1% now)

So I applaud their very recent efforts to finally mention some vague goals away from Low Earth Orbit. L1 is a fine stepping stone, but Mars is where the public eye is. Nasa administrator Daniel Goldin had some brave words about the possibility of sending men to Mars in this decade or the next, but Bush put a bean counter in charge of Nasa pretty quickly to throttle cost overruns from the ISS.

What we really need is a president giving NASA a kick in the pants, and the funding to follow, as Kennedy did. Either that or wait around for private space exploration to become worthwhile, and we're going to be waiting quite a while in that case. Another space race? maybe China? I hope so. Because the current NASA schedule is anything but ambitious.

After the Apollo missions, there was no budget to keep up the plans for the Apollo V spacecraft. If NASA wanted to land men on the moon again, they would have to reinvent the great rocket science of Wernher von Braun. NASA should just shoot for going to the moon now and establishing a science based set of missions.

Apollo was not built around science. It was built as another battlefield of the Cold War. The space program wasn't even important until the Soviet Union beat America into space. When NASA can make routine, scientific trips to the moon, then they can concentrate on building a space station at L1 and worry about getting to Mars.

The Space Shuttle is routine now, and usually stays within budget. NASA should build on this technology, slowly and gradually. We will learn so much more this way rather than putting a thermometer and a seismometer on the moon as quickly as possible.

Not to be picky, but this is Slashdot. Picky is what we do here. The rocket for the lunar Apollo missions was the Saturn V series booster, not the Apollo V.

The Saturn series was used after the Lunar Apollo four times (correct me if I'm wrong). Three were Apollo CSMs (one to ASTP, two to Skylab), and one, a Saturn INT-21 (a modified Saturn V) boosted Skylab, which really was a good scientific experiment, to orbit.

Did any of the astronauts who went to the moon come down with cancer? They got beyond the earth's magnetic field and the shielding on the apollo spacecraft might not have beengood enough either. (guess we need the deflector array offthe USS Enterprise?)

Which would you rather have? Landings on all the major planets, together with exploratory rovers, chemical analyses, and photography, and space telescopes looking for planets around nearby stars? Or a handful of aging space cowboys spending a lot of their time cleaning toilets and keeping in shape at the Lagrange point? I know which one I would rather have.

Sure, it would be fun to go into space in person. But that's entertainment and tourism, and the best way to finance that is through private funding. It's the science, the big questions, that require government funding, and there we should concentrate on what gives the biggest payoff--and that is unmanned space flight with robotic probes.

IANARS (rocket scientist) but what are the possibilities of utilizing the asteroid just discovered that shares the earths orbit for some form of station. A snippet from this article: http://news.bbc.co.uk/2/hi/science/nature/2347663. stm

"Although only about 100 metres across 2002 AA29 may play a role in the manned exploration of space out of all proportion to its size.

Already researchers are speculating that it could be visited by an unmanned spaceprobe or even become the first object after the Moon to be stepped on by astronauts.

The object could tell us a lot about the composition of asteroids.

Some have speculated that it could be nudged into a permanent Earth orbit where it could be studied at greater length."

If you could nudge this thing into the right orbit wouldn't it make a wonderful station? Lots of room, some raw materials, and you could burrow into to escape the radiation. I understand that some asteroids are nothing more than loose collections of rocks and dust. But it's an intriguing, and plausible idea.

now that you have publicised the radiation risk, there is no way that Nsync singer will go into space... and there dies our last chance of getting him sterilised and stopping him from having offspring...

I've long felt that human progress into space has been on some form of hold since the 1960s. JFK announced that we would goto the moon not many years before we actually did. Then we went back a couple of times. Then not much.

The major achievement of the late 70s was the Space Shuttle. The major achievement of the turn of the century will be the ISS. Obviously these are significant achievements but why we haven't been back to the moon in 40 years is baffling.

I'm very happy to see a station being considered that won't just be in orbit. I hope it is a sign of things to come. I'd really like to see a moon base in my lifetime. I don't know much about space but I'd expect it must be easier to build a big station if you build it on something.

We need to be up there. In large numbers. We need private industry up there. NASA should be focussing on putting human living quarters in space and providing transportation up there. I think there should be some kind of space oriented general contracting agency focussing on getting as many people up there for as long as possible. We need scientists, professors, entrepeneurs, the media...all sorts of people to go up and see what we can make of it.

If space really is the new frontier, it should be accesible. I hope this is a step in the right direction.

I thought Lagrange points collected a lot of dust, which would be bad for optics. Its not like you can vacuum that stuff up either. If you are 5/6ths of the way to the moon already, why not just go the rest of the way? A luna's gravity keeps the dust down and provides many other benefits. I expect Luna would also supply SOME building materials, like maybe 10 foot thick rock walls to stop cosmic rays, for example. The lunar gravity would be a disadvantage for launching other missions from there, but perhaps that could be compensated for.

If there are more informed people out there who see what I don't, I'd love to hear it.

I thought Lagrange points collected a lot of dust, which would be bad for optics.

L4 and L5 are gravitationally stable points, so there may be collections of dust there. (In the Jupiter-Sun L4 and L5 points, there are collections of asteroids.)

But L1, L2, and L3 are all gravitationally unstable. A body at one of those three points will tend to fall away from the point rather than staying in it.

L4 and L5 are like being at the bottom of a depression: whichever way you go, gravity tends to pull you back toward the middle. L1, L2, and L3 are more like being at the top of a hill. If you're right at the very center, you're fine. But if you're even slightly off-center, gravity will pull you down the hill.

In theory, L1 ought to be the cleanest point between the Earth and the moon. Nothing can stay in orbit at L1 without active station-keeping.

Many here have spoken of the "insane" "horrendous" "crazy" amounts of money spent on IIS. How many think that this money was spent *mostly* to make sure that no one died?

Was it a good thing to spend that money on? Is the IIS over-engineered in favour of preventing un unfortunate death? (Aside - How many of you, after viewing the interior of an Apollo era craft, would still go into space in one of those?)

Let's look at a little history. If during the 18th century, we had spent an equivalent amount of dough on sailing ships (with the (un)stated goal of preventing deaths (monarchs HATE to look bad)) I think we'd still be looking for our assholes with a mirror. We'd never have left Europe. The economy of the day would not have tolerated it.

My father-in-law was one of the Canadians who helped develop the nuclear power station system called CANDU. His stories are quite telling. His take on risk? - during development of CANDU the engineering studies required would fill a couple of banker's boxes. Today, those studies would fill a small stadium. With a exponential rise in cost. Why? What's the return? A couple of lives? A dozen lives?

My point is - we have tried to reduce the risk to zero and this is not only stupid, but unwise. Stupid because there will always be a risk. How much money are we going to let timid politicians/bureaucrats spend on that last.005% of risk reduction? Unwise, because we lose the ability to pursue our dreams. We're deadlocked.

"Acceptable risk" is a term that has been lost from the West's vocabulary and it is time to bring it back.

That's great. You don't want to spend a few more dollars to make sure someone doesn't die. How about we compromise. You spend most of your life researching so that you're valuable enough to be sent into space, and then, risk your life to go up into space, and we won't spend a dime to make sure you come back alive. Deal?

While reading about the problems with radiation shielding, I came up with perhaps one way they could reduce exposure: Add improved shielding to the sleeping closets. If they can cut out 90% of the radiation in an area that the average astronaut will spend 30% of his or her time in, that`s a significant savings for relatively little added weight.

Putting a space station at the Earth-Moon L1? snort What yahoo at NASA HQ came up with that one? They obviously didn't bother to check with anyone who actually knows anything about libration points.

Why is this stupid? Here's why:

The Earth-Moon L1 is an unstable point. Put something there (if you can), and it will immediately drift away.

Yes, there are these things called halo orbits and lissajous orbits, that are essentially periodic orbits around the libration points, but their dynamics are very complex.

Did I mention that the dynamics in this region is very complex? Actually getting onto a halo or liss is not anywhere near as simple as computing a hohmann transfer - it takes a lot of careful precalculation. The region around the L1 point (and all libration points) is governed by three-body dynamics - highly nonlinear, potentially chaotic, very messy to deal with.

Even assuming that you successfully put your space station at L1, how the hell are you going to get anything else to rendezvous with it? (see previous point) I can't even imagine trying to carry out docking maneuvers in that kind of gravitational environment.

The reason it's cheap to get to a halo (the efficient "superhighway" they keep talking about) is that you can hop on the stable manifold associated with the halo (essentially a sheaf of trajectories that asymptotically approach the halo) where it passes near the earth. But this cuts both ways, since the halos also have unstable manifolds that lead away from the halo (and are also cheap to get onto). One small burn in the wrong direction, and "whoops!", you're on the unstable manifold leading away from the halo and off to who knows where.

So what do you have when you break it down: A dynamically complex region of space that will make proximity maneuvers extremely difficult to perform. And if you make one small mistake in those difficult maneuvers, you're basically headed for Pluto. Bottom line: L1 is just about the stupidest place to put a space station that you could pick.

Let's see, NASA, you know the people who send space probes galavanting around the solar system slingshotting around the sun, planets, moons etc... to reach their final destination thinks that building a space station in an L1 point is a good idea. Obviously, you know better than NASA and don't try to figure out why they'd pick L1 over say L4 or L5. *sigh*

While maintaining position at L1 is technically more challenging than maintaining position at L4 or L5, it has a higher payoff. For one, you won't be trying to build your space station in a veritable gravel pit in space. Secondly, it's trivial to launch vehicles from the point - you just let them go and they'll drift off without active station keeping. And considering how the intended primary purpose would be as a place to launch other missions from, that's a slightly useful thing.

Others have already pointed out various reasons that your smug troll is off-base. I'll just add that it's dangerous to put things in the L4 or L5 points because they are stable, and therefore filled with potentially dangerous space junk.

If it's really so hard to put things at L1 and keep them there, you better go tell the SOHO team [nasa.gov] who have successfully kept that satellite at the Sun-Earth L1 point for almost 7 years now, without ever being "headed for Pluto".

It's good to see this discussion informed by some knowledge of orbital mechanics (a lot more than I have, obviously). For those of us playing catch-up here, some links:
1 [caltech.edu]
2 [vt.edu]
3 [stk.com].

This is obviously a richly researched topic with lots of published papers. Some [ieec.fcr.es] of them talk about new algorithms for tackling the complex dynamics you're talking about. And of course there's always Moore's Law; the computers used for Apollo missions were about as powerful as (or maybe much less than?) Palm Pilots.

It's probably quite feasible to give the L1 station a radio link to an orbital mechanics cluster on the ground, which can be as big as is needed, and could run equations of motion for a couple dozen nearby orbits in faster-than-real-time.

Useful in what sense? There's nothing on the moon that we need or want, at least not with current technologies at hand. If you put some kind of space station in a gravitationally unstable point, like L1, then you can use it to launch trips to points elsewhere very inexpensively. (Assuming the cost of maintaining the orbit of the L1 station turns out to be manageable.) Once you're at L1, you've basically spent all the energy you need to spend to get out of the Earth-moon system. Refueling or restaging at L1 for longer trips to Mars and elsewhere makes a lot of sense.

Science fiction from the late 1900's aside, moon bases just don't make that much sense right now.

In most harder sci-fi I've read, stations are rings around docking spaces rotating at sufficient speed to simulate gravity. How well does this work?

It's pretty much indistinguishable from the real thing. The only noticable phenomenon that would indicate otherwise would be the decreasing gravity as you go 'up' towards the center of the hub.

To get the gravity simulation, do you have to be strapped into a chair?

Certainly not! Ever been on the Gravitron [optushome.com.au]? Spins around really fast and throws everything in it at the walls at a couple of G's. Same principle.

A moon base could have a banked rotating surface to help enhance the puny natural gravity of the moon, couldn't it?

Quite correct. Not sure it's worth the trouble on a large scale, though. It would have to spin nearly vertical (relative to Luna's surface). I estimate that you'd have to spin it up to 0.91 G at the edge to augment the puny gravity there to a full 9.8 m/s^2. And the 'floor' of the habitat would be at a good 66 degrees relative to the ground. Changing the spin rate would actually change where 'down' pointed to (faster->more lateral, slower->more vertical). Any attempts to get in or out of the hub would have to be done right at the center, which is fine for a space station but would suck for a surface colony. It'd certainly be useful as an exercise gym or maternity ward, though.

Third-body perturbations? Anything too big to capture that comes by them would tend to remove the clutter. The Earth-Moon and Earth-Sun systems aren't anything like, say, Jupiter's. Now there's a junkyard!

The article talks about IONS colliding with atoms and causing secondary radiation. I would like to get clarification on this point.

If it really is ions causing the problem then a strong magnetic field should provide some protection, just as the earth's field does. In fact the article talks about a significant increase in radiation when outside the earth's magnetic field.